Air Force X-37B UOV (unmanned orbital vehicle), launched last March [PHOTO], is still in orbit despite its official orbital endurance of only nine months. This is largely because it carried with it a large solar panel, which came out of the cargo pay, unfolded and produced enough power to keep the X-37B up there for much longer. No one is saying how much longer. Nor is there any information about what the X-37B [PHOTO] has been doing up there all this time. The air force has revealed that it is designing an X-37C, which would be twice the size of the X-37B and able to carry up to six passengers. Think of it as Space Shuttle Lite, but robotic and run by the military, not NASA. This has the Chinese worried, and they are not being quiet about their fears.

A year ago, after seven months in orbit, the first X-37B flight (of 224 days) ended. Three months later, the second X-37B was launched. The X-37B also demonstrated that it could not be easily tracked while in orbit.

Ever mysterious, the X-37B proved elusive to amateur astronomers. Little is publicly known about what either X-37B was doing up there. The best guess is that it testing the endurance of new satellite components. That does not give amateur astronomers much to look at. The international collection of amateur sky watchers have proved remarkably adept at spotting orbital objects in the past, including classified ones like the X-37B. But not this time. The air force said this flight was simply to test the aircraft, but would not say what, if anything, was in the cargo bay for the first flight. It was revealed that the second one took up a folded solar panel. No details on what other items were tested. The amateur orbital observer community has concluded that one thing the X-37B tested was how well it could constantly switch positions, and stay hidden. In that respect, the X-37B was a resounding success. That's because these amateur observers are generally very good at tracking what's up there.

One notable incident occurred three years ago, when a U.S. spy satellite fell out of orbit (apparently because of a failure in its maneuvering system). The amateur astronomers were able to track it. If this had not been an American reconnaissance satellite, there would have been no media attention to this, because 4-5 satellites a month fall back to earth. Since most of the planet is ocean, or otherwise uninhabited (humans like to cluster together), the satellites tend to come down as a few fragments, and rarely is anyone, or anything manmade, hit.

Before the Internet became widely used a decade ago, you heard very little about all these injured or worn out space satellites raining down on the planet. But with the Internet, the many thousands of amateur astronomers could connect and compare notes. It was like assembling a huge jigsaw puzzle. Many sightings now formed a pattern, and a worldwide network of observers made visible the movements of hundreds of space satellites. These objects were always visible at night, sometimes to the naked eye, but unless you knew something about orbits and such, they could be difficult to keep track of. These days, a lot of the activity is posted and discussed at http://www.satobs.org/. But the X-37B has proved elusive, and became a frustrating challenge to the amateur sky watchers. This is pleasing to American air force officials, who designed the X-37B to be elusive to terrestrial observation.

The X-37B is a remotely controlled mini-Space Shuttle. The space vehicle, according to amateur astronomers (who like to watch spy satellites as well), appears to be going through some tests. The X-37B is believed to have a payload of about 227-300 kg (500-660 pounds). The payload bay is 2.1x1.4 meters (7x4 feet). As it returned to earth, it landed by itself (after being ordered to use a specific landing area.) The X-37B weighs five tons, is nine meters (29 feet) long and has a wingspan of 4 meters (14 feet). The Space Shuttle is 56 meters long, weighs 2,000 tons and has a payload of 24 tons.

The X-37B is a classified project, so not many additional details are available. It's been in development for eleven years, but work was slowed down for a while because of lack of money. What makes the X-37B so useful is that it is very maneuverable, contains some internal sensors (as well as communications gear), and can carry mini-satellites, or additional sensors, in the payload bay. Using a remotely controlled arm, the X-37B could refuel or repair other satellites. But X-37B is a classified project, with little confirmed information about its payload or mission (other than testing the system on its first mission). Future missions will involve intelligence work, and perhaps servicing existing spy satellites (which use up their fuel to change their orbits.) The X-37B is believed capable of serving as a platform for attacks on enemy satellites in wartime.